1. Technical Field
The present disclosure relates to a method of fabricating a metal interconnection and to a method of fabricating an image sensor using the same.
2. Description of the Related Art
An image sensor may transform optical images into electrical signals. Recent advances in computer and communication industries have led to a strong demand for high performance image sensors in various consumer electronic devices including, for example, digital cameras, camcorders, PCS (Personal Communication System), game devices, security cameras, and medical micro-cameras.
Specifically, a Metal Oxide Semiconductor (MOS) image sensor can be driven easily and implemented using various scanning methods. Also, the size of a product can be minimized as digital signal-processing circuits can be integrated into a single chip, and the fabricating cost can be reduced as MOS process technology can be reused. In addition, low power consumption makes it easy to apply MOS image sensors to battery-powered products. Therefore, with the advances in implementation of high resolution MOS image sensors, the use of MOS image sensors has rapidly increased.
Moreover, a MOS image sensor may include a photoelectric transformation device which absorbs incident light and accumulates the corresponding charge and multi-layer metal interconnections to output charges accumulated in the photoelectric transformation device. For the metal interconnections, aluminum or copper interconnections are widely used. As MOS image sensors become miniaturized, the copper interconnections are becoming more widely used as the copper interconnection may have lower specific resistance and can be formed in narrow patterns.
When forming copper or aluminum interconnections, a plasma etching process is used, and such process can cause damage to the photoelectric transformation device which can increase a dark level of output signals.